1. Field of Invention
The present invention relates to an air spring for a vehicle, and more particularly, to an air spring for a vehicle which simultaneously performs the functions of shock-absorbing and vertical movement of a pusher system.
2. Description of Related Art
Freight cars such as trucks may be additionally equipped with pusher and tag systems on the rear wheel shaft to increase the load of freight.
FIG. 1 is a view showing the structure of a pusher system according to the related art. Referring to FIG. 1, the pusher system includes ride air springs 3 between the car body 2 and the axle 1 to absorb shock and clamp beams 4 that are held by the ride air springs 3 and support the axle 1 with wheels at both ends. Lift air springs 5 for lifting or descending the axle 1 are disposed at the front ends of the clamp beam assemblies 4.
Weight distribution on the front and rear shafts is possible by the air pressure from air springs for traveling, while air springs for lifting not only prevent friction of tires, but also improve riding comfort and fuel efficiency because vehicles without a load travel with the axle lifted, and when the vehicles are loaded, the pusher axle and the tag axle are descended for use.
The pusher system of the related art, however, has a problem in that since the ride air springs for shock-absorbing in traveling and the lift air springs for lifting and descending the axles are separately mounted, the structure of a vehicle is complicated and the number of parts increases, and therefore the manufacturing cost and the weight are increased.
However, this system also has a problem that the manufacturing cost and the weight are increased, because ride air springs and lift air springs are separately mounted.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.